1962 Ohio state highway renumbering
In 1962, the Ohio Department of Highways implemented the system of Interstate Highways that had been approved by the states in 1956.
The State Route numbers 70, 71, 74, 75, 77, 80, 90, 270, 271, 275, 277, 280, 290, 675, and 680 conflicted with new designations, so the State Routes with those numbers were renumbered. However, there is no Interstate 290 in Ohio anymore, so 290 is a possible state route number again.
| New | Old | From | To |
| Cincinnati | Athens | ||
| Covington | Greenfield | ||
| Greenfield | Aberdeen | ||
| Vermilion | Loudonville | ||
| East of Nashville | West Virginia border in Marietta | ||
| Akron | West Lafayette | ||
| West Lafayette | Ironton | ||
| North Kingsville | Petersburg | ||
| Petersburg | Calcutta | ||
| Edinburg | Sandyville | ||
| Chillicothe | Mount Sterling | ||
| Perrysburg | Perrysburg | ||
| Rosewood | Marysville | ||
| Salem Township | Wayne Township | ||
| Trimble | Amesville | ||
| Amesville | Guysville | ||
| Martinsburg | Birmingham | ||
| Indiana | New Carlisle | ||
| Mineral | Reedsville | ||
| Buchtel | Trimble Township | ||
| Stone Creek | West Lafayette | ||
| Washington Court House | Greenfield | ||
| Greenfield | South of Cynthiana | ||
| Southwest of Shreve | East of Nashville |
Other renumberings due to new interstate designations after 1962
- In 1972, due to the designation of I-76 in Ohio, Ohio State Route 76 had the part north of Beverly renumbered to Ohio State Route 83 and the rest became a southward extension of Ohio State Route 339.
- In 1973, due to the designation of I-670 in Ohio, Ohio State Route 670 had the portion east of Ohio State Route 313 become an extension of it and the rest was renumbered to Ohio State Route 761.